OhioKnight:FTFA It's a collection of quasars that measures a difficult-to-imagine 4 billion light-years across, Space.com reports. To put that in perspective, the entire Milky Way is about 100,000 light-years wide.

Ummm, let me try.

To put that in perspective, the distance to the edge of the observable universe is about 12 billion light-years.

So this thing takes up 1/3 the diameter of the entire known universe and we only discovered it now?

More info in this link. There are 73 quasars in the cluster, and it's 9 billion light years away. Can you imagine the mass of these things, only 73 of them in 4 billion light years of space, and they're still noticeably tied together via gravity?

So here's a thought: Is this going to end up effecting theories on dark matter/dark energy? That's gotta be a hell of a lot of mass out there that we didn't know about before, and might there not be more of these out there for us to find?

moviemarketing:OhioKnight: FTFA It's a collection of quasars that measures a difficult-to-imagine 4 billion light-years across, Space.com reports. To put that in perspective, the entire Milky Way is about 100,000 light-years wide.

Ummm, let me try.

To put that in perspective, the distance to the edge of the observable universe is about 12 billion light-years.

So this thing takes up 1/3 the diameter of the entire known universe and we only discovered it now?

We haven't been able to see the entirety of the observable universe yet. Most of it is too dim to see with your eyes even with a telescope - a lot of these mapping discoveries are being made with very long exposures on very sensitive instruments (x-ray, radio, as well as visible light). And they only see a tiny, tiny part of the sky at once. It's going to take a while. (And more funding for astronomy & other sciences couldn't hurt either!)

moviemarketing:So this thing takes up 1/3 the diameter of the entire known universe and we only discovered it now?

TFA doesn't describe well what is meant by "structure." This isn't a 4BLY long concrete wall. It's several dozen quasars massive enough to be gravitationally bound to each other despite great distances between them. The Virgo Cluster of galaxies, of which the Milky Way is one, is considered a "structure" as well. But look up in the northern hemisphere's night sky, and you're lucky if you can make out one other galaxy with the naked eye (Andromeda).

In Carl Sagan's Contact, he wrote about how the aliens had figured out that the Universe was expanding too fast and they were building massive structures to use their gravity to slow down the expansion.

Niveras:You know an even larger structure than that quasar group? The universe. Gravity is ostensibly infinite, even if it attenuates to a degree that its effect cannot overcome inertia, which means that all objects are tied to some degree, that all are part of one 'structure.'

100 Watt Walrus:AdolfOliverPanties: So how the fark did this go unnoticed for so long?

moviemarketing: So this thing takes up 1/3 the diameter of the entire known universe and we only discovered it now?

TFA doesn't describe well what is meant by "structure." This isn't a 4BLY long concrete wall. It's several dozen quasars massive enough to be gravitationally bound to each other despite great distances between them. The Virgo Cluster of galaxies, of which the Milky Way is one, is considered a "structure" as well. But look up in the northern hemisphere's night sky, and you're lucky if you can make out one other galaxy with the naked eye (Andromeda).

Are they actually gravitationally bound to each other? That seems highly implausible to me. I always thought that things like this were just deviations from the mean in an organized way. Like a line of quasars across the universe that couldn't have formed by chance, but still doesn't necessarily have to interact in any way in the present, just (presumably) in the past.

I really am surprised it took this long to find it - and NO, they aren't going t find anything bigger.

We didn't see it because the visible light it emits is dim by the time it gets here, but the only thing bigger than it in the night sky is the Milky Way (and that is just the smear of billions of stars in our own galaxy.

If this thing was bright enough it would dominate the sky. It is over 25 degrees across when viewed from Earth.... the MOON is only half a degree across. So imagine 50 moons lined up edge to edge - HUGE!

spcMike: In Fred Pohl's "Gateway" energy-based beings didn't think this matter-dominated universe was hospitable to life as they knew it. They wanted to speed up the contraction of the universe to tweak the next Big Bang. I think that's more likely.

Abner Doon:Are they actually gravitationally bound to each other? That seems highly implausible to me.

Just because you don't understand it (and Heaven knows I don't either) doesn't mean it doesn't exist.

I always thought that things like this were just deviations from the mean in an organized way. Like a line of quasars across the universe that couldn't have formed by chance, but still doesn't necessarily have to interact in any way in the present, just (presumably) in the past.

According to the up-until-today accepted theories, "organized" things can't be this big. Science advanced a little today -- something broke a theoretical limit!

PonceAlyosha:I don't exactly understand how this is any less isomorphic than any other large scale structure. Sure, it's big, but isn't that just a matter of perspective? If the universe is truly infinite in spatial dimensions, shouldn't these sort of things be not exactly uncommon? Then again, before this wasn't the largest "structure" one of the voids between filament groups?

It can't be infinite in spacial dimensions. It started as a small point and a finite amount of time has passed. For it to be infinite in size it would have to have expanded with infinite speed.

spcMike:In Carl Sagan's Contact, he wrote about how the aliens had figured out that the Universe was expanding too fast and they were building massive structures to use their gravity to slow down the expansion.

This is probably part of that effort.

Hmmm.... So... where did they get the extra mass, that was not already there?

A basic understanding of the Big Bang will tell you that the universe cannot be homogenous completely, otherwise no stellar fusion would've occurred, no supernovas, no heavy elements, and thus no planets or us. (and no LQGs for that matter). Astronomers need to get more astrophysics.

Just Another OC Homeless Guy:spcMike: In Carl Sagan's Contact, he wrote about how the aliens had figured out that the Universe was expanding too fast and they were building massive structures to use their gravity to slow down the expansion.

This is probably part of that effort.

Hmmm.... So... where did they get the extra mass, that was not already there?

madgonad:Just Another OC Homeless Guy: spcMike: In Carl Sagan's Contact, he wrote about how the aliens had figured out that the Universe was expanding too fast and they were building massive structures to use their gravity to slow down the expansion.

This is probably part of that effort.

Hmmm.... So... where did they get the extra mass, that was not already there?

poonesfarm:AdolfOliverPanties: So how the fark did this go unnoticed for so long?

Space is big. Really big. You just won't believe how vastly, hugely, mindbogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space, listen...

That's right folks, due to expansion of the universe, the observable edge from here is 46-47 Billion Light Years away. That makes this thing (gravitationally attracted to each other group of things) still only 4.3% the length of the observable universe.

We're still awaiting results from the Planck satellite to give us more detailed info on Dark Flow. I'm more curious as to what kinda mass the thing that is causing that to be. Saying "Large Quasar Group" gives you some wiggle room to name stuff that you'll find later.